Annual occupational exposure to ultraviolet radiation in central Queensland

Ultraviolet radiation thin film dosimetry: A review of properties and applications

Spectroradiometry, radiometry, and dosimetry are employed for the measurement of ultraviolet radiation (UVR) irradiance and non-ionizing exposure. Different types of UVR dosimeter have been developed for measuring personal and environmental UVR exposures since film dosimetry was pioneered in the 1970s. An important type of dosimeter is the thin film variant, which contains materials that undergo changes in optical absorbance when exposed to UVR. These changes can be measured at a specific wavelength using a spectrophotometer. Thin film dosimeters allow UVR exposure measurements on humans at various body sites during daily activities, as well as on plants, animals, and any sites of interest when utilized in a field environment. This review examines the properties and applications of five types of thin film UVR dosimeter that have different dynamic exposure limits and spectral responses. Polysulphone, with a spectral response approximating the human erythema action spectrum, was one of the first materials employed in thin film form for the measurement of UVR exposures up to 1 day, and up to 6 days with an extended dynamic range filter. Polyphenylene oxide has been characterized and employed for personal UVR exposure measurements up to approximately four summer days and has also been used for long-term underwater UVR exposures. Phenothiazine and 8-methoxypsoralen have been reported as suitable for the measurement of longer wavelength UVA exposures. Finally, polyvinyl chloride with an extended dynamic exposure range of over 3 weeks has been shown to have predominantly a spectral response in the UVB and extending up to 340 nm.

UVR Exposure and Prevention of Street Construction Workers in Colombia and Germany

(1) Solar ultraviolet radiation (UVR) poses a major risk factor for developing skin cancer after years of chronic exposure. The irradiation is strongly dependent upon the activity or occupation carried out, but also on the climate conditions at the workplace. Knowledge of both has been tested within the occupational group of road construction workers in Colombia and Germany. (2) The GENESIS-UV measurement system has been used at both locations for consistency. A number of workers in both countries wore an electronic data logging dosimeter for several months to deliver detailed information on UVR exposure. (3) It was found that in a tropical climate, UVR exposure remains constant throughout the year, while in a temperate climate seasonal effects are visible, superimposed by behavioural aspects e.g., in springtime. The daily distribution of the radiation shows a distinct dip, especially in the Colombian data. Derived data show the high fraction of working days exceeding a threshold set by the skin type. (4) Road construction work involves high UVR exposure. In both countries, preventive measures are required to reduce the personal exposure to a minimum. Exceedance of the minimal erythema dose (MED) suggests a possible enhancing effect, especially in fair skinned people. Intercomparison of UVR exposure at workplaces is possible between countries and climate zones, emphasizing efforts for global action against skin cancer.

Review on Occupational Personal Solar UV Exposure Measurements

During leisure time, people can decide if they want to expose themselves to solar ultraviolet (UV) radiation and to what extent. While working, people do not have this choice. Outdoor workers are exposed to solar UV radiation (UVR) on a daily basis. This may pose a certain health risk, which can be estimated when the personal solar UVR exposure (PE) is known. During past decades, a variety of studies were conducted to measure PE of outdoor workers and our knowledge of the PE of outdoor workers has increased remarkably. As shown by this review, studies clearly indicate that PE of most outdoor workers exceeds the internationally proposed threshold limit value, which is comparable to 1.0 to 1.3 standard erythema dose (SED), respectively, to 1.1 to 1.5 UV Index received over one hour. Besides working in a high UVR environ, monotonic workflow (limited movement, nearly static posture) is a risk factor. In such cases, PE can be higher than ambient UVR. In this review, we provide also a list of milestones, depicting the progress and the most important findings in this field during the past 45 years. However, in many respects our knowledge is still rudimentary, for several reasons. Different measuring positions have been used so that measured PE is not comparable. Few studies were designed to enable the extension of measured PE to other locations or dates. Although the importance of a proper calibration of the measuring devices in respect to the changing solar spectrum was pointed out from the beginning, this is often not performed, which leads to high uncertainties in the presented PE levels. At the end of our review, we provide some key points, which can be used to evaluate the quality of a study respectively to support the design of future studies.

Comparison between EPA UV index app and UV monitor to assess risk for solar ultraviolet radiation exposure in agricultural settings in Eastern North Carolina

Agricultural workers are exposed to solar ultraviolet (UV) radiation due to the significant amount of time spent working outdoors. Risk information on UV exposure from the EPA SunWise UV Index mobile app is conveniently available for timely advice on risk management, but its reliability is unknown. The purpose of this study was to determine the reliability of the EPA UV Index app in providing accurate risk information to reduce UV exposure and prevent related illnesses among agricultural workers in eastern North Carolina. UV radiation effective irradiance (UV _eff ) indices were datalogged at two agricultural sites using radiometers from April-August 2019 and were assigned to risk levels (low, moderate, high, very high, extreme) based on the ACGIH^® Threshold Limit Values (TLVs^®). The UV index (UV _app ) and its corresponding risk level were obtained using the app. Hourly UV _app -based risk level assignments were time-matched to their corresponding UV _eff /TLV-based risk level assignments (871 pairs) and analyzed using cross tabulation by determining the percentage of hourly UV _eff /TLV-based risk levels ("gold standard") with the same hourly UV _app -based risk levels, with a larger percentage indicating higher app reliability. Results showed that the app correctly identified 100% of low risk conditions, but its reliability decreased as the UV risk condition became more severe. The app correctly identified 0% of moderate, high and very high risk conditions but instead assigned 100% of them to lower risk levels (30-100% as low risk, 5-70% as moderate risk), indicating that the app was less protective in assessing UV risk. The app correctly identified 0.6% of extreme risk conditions but assigned 99.4% of them to lower risk levels (9.4% as low, 29.7% as moderate, 24.6% as high, 35.8% as very high). It is concluded that the performance of the EPA UV Index app in assessing occupational UV risk is not protective of workers particularly for high risk conditions, and that the use of the app for the assessment of risk to UV exposure in agricultural settings is not recommended.

Evaluation of the Long-term Cumulative UVA Facial Exposure of Queensland School Teachers derived for an Extended Period from the OMI Satellite Irradiance

This research presents a novel methodology for deriving the total daily broadband solar UVA (320-400 nm) received by school teachers during their working day from Ozone Monitoring Instrument (OMI) satellite solar noon UVA irradiance measurements for a Queensland subtropical site (27.5°S, 152°E). Daily UVA exposures are weighted to the anatomical human cheek (anterior infra-orbital region) for teachers wearing and not wearing broad-brimmed hats. The method utilizes the OMI UVA irradiance data collected daily at high temporal resolution over 2005 to 2016 to derive the total daily UVA exposure to a horizontal plane. These horizontal plane exposures are scaled by factors to take into account the timing of outdoor activity. The relationship between exposures to a horizontal plane and those to a vertical plane and the protection provided by a broad-brimmed hat was assessed to evaluate the total daily UVA exposures to the cheek for classroom and physical education teaching staff expected to be outside at different periods of the day. The developed method enables the total daily UVA exposure to specific anatomical sites to be evaluated from the satellite solar noon irradiance at locations that do not have access to surface-based instrumentation capable of recording in the solar UVA waveband.

Seasonal Minimum and Maximum Solar Ultraviolet Exposure Measurements of Classroom Teachers Residing in Tropical North Queensland, Australia

The risk of keratinocyte skin cancer, malignant melanoma and ultraviolet radiation (UVR)-induced eye disease is disproportionately higher in Australia and New Zealand compared to equivalent northern hemisphere latitudes. While many teachers are aware of the importance of reinforcing sun safety messages to students, many may not be aware of the considerable personal exposure risk while performing outdoor duties in locations experiencing high to extreme ambient UVR year-round. Personal erythemally effective exposure of classroom teachers in tropical Townsville (19.3°S) was measured to establish seasonal extremes in exposure behavior. Mean daily personal exposure was higher in winter (91.2 J m^-2 , 0.91 Standard Erythema Dose [SED]) than summer (63.3 J m^-2 , 0.63 SED). The range of exposures represents personal exposures that approximate current national guidelines for Australian workers at the study latitude of approximately 1.2 SED (30 J m^-2 effective to the International Commission on Non-Ionizing Radiation Protection). Similar proportions of teachers spent more than 1 h outdoors per day in winter (28.6%) and summer (23.6%) as part of their teaching duties with seasonal differences having little effect on the time of exposure. Personal exposures for teachers peaked during both seasons near school meal break times at 11:00 am and 1:00 pm, respectively.

Prevalence and factors associated with exposure to sunlight and sunscreen among physical education teachers in Pelotas, southern Brazil

BACKGROUND

Decreasing the time of exposure to the sun and increasing sunscreen use are important actions to prevent skin cancer.

OBJECTIVE

This study aimed to verify the prevalence of exposure to the sun and the use of sunscreen, as well as associated factors among physical education teachers of the basic education network from city of Pelotas, southern Brazil.

METHODS

A census type study was conducted with physical education teachers of the basic education network from Pelotas. This study assessed the time of exposure to the sun in the workplace for at least 20 min, between 10am and 4pm, and the use of sunscreen during the workday.

RESULTS

188 teachers answered the questionnaire. The prevalence of exposure to the sun between 10:00am and 4:00pm was 89.2% (95% CI of 83.8% -93.3%), while sunscreen use was 63.3% (95% CI of 56.0% -70.2%). However, when the sample was stratified by sex, women reported a higher rate of sunscreen use (78.5% -95% CI of 72.2-84.3) than men (38.9% -95% CI of 31.8-46.2) (p<0.001). Teachers with longer work weeks were at greater risk of exposure to the sun. In addition, women, with normal weight and who worked less hours, were more likely to use sunscreen.

STUDY LIMITATIONS

Cross-sectional study and lack of information on the proper use and frequency of use of sunscreen.

CONCLUSION

Physical education teachers were highly exposed to solar radiation, and less than two-thirds used sunscreen during the workday. Interventions with this professional group are necessary to reduce the risk of skin cancer.

Assessment of occupational exposure to heat stress and solar ultraviolet radiation among groundskeepers in an eastern North Carolina university setting

Groundskeepers spend most of the year working outdoors, exposing them to heat and solar ultraviolet (UV) radiation and increasing their risk to related adverse health effects. Various studies on heat and UV exposures in different occupations have been published, but those on groundskeepers are rare. The purpose of this study was to assess the exposure to heat stress and solar UV radiation among groundskeepers in an eastern North Carolina university setting. Wet bulb globe temperature (WBGT) index using a heat stress monitor and UV effective irradiance (UV_eff) index using a digital UV meter were recorded in various work areas three times a day (morning, noon, afternoon) and during three seasons (spring, summer, fall). Data analysis was conducted using descriptive statistics, analysis of variance (ANOVA), Tukey Honestly Significant Difference (HSD), and Pearson Correlation tests. The mean (±SD) WBGT index was the highest in the afternoon (25.4 ± 5.0°C), summer (27.8 ± 3.1°C), and July (29.0 ± 2.6°C); the mean UV_eff index was the highest at noon, summer and June (0.0116 ± 0.0061, 0.0101 ± 0.0081, and 0.0114 ± 0.0089 mW/cm², respectively). Differences in the mean WBGT and UV_eff indices within the time periods of day, seasons and months were significant (P < 0.01). The overall correlation between WBGT and UV indices was moderate (r = 0.42, P < 0.01) but lack of correlation was found during different times of the day during the fall and summer seasons. The largest percentages of WBGT indices exceeding the American Conference of Governmental Industrial Hygienists (ACGIH) threshold limit values (TLVs) for different workloads were found in the afternoon (11.3-40.7%), summer (14.6-56%), and July (28.8-76.3%). The mean UV_eff for noon (0.0116 mW/cm²) and afternoon (0.0100 mW/cm²) exceeded the TLV for 30-min exposure. This study shows that groundskeepers are potentially exposed to excessive heat stress and UV radiation, and are at risk to developing heat- and UV-related illnesses. The study findings will be beneficial in implementing recommended control measures to prevent heat stress and UV exposure among groundskeepers and other similar outdoor workers.

Risk Assessment of Face Skin Exposure to UV Irradiance from Different Rotation Angle Ranges

Ultraviolet (UV) is one of the environmental pathogenic factors causing skin damage. Aiming to assess the risk of face skin exposure to UV irradiance from different rotation angles, a rotating model was used to monitor the exposure of the skin on the face to UV irradiance, with skin damage action spectra used to determine the biologically effective UV irradiance (UVBE_skin) and UVBE_skin radiant exposure (HBE_skin) causing skin damage. The results indicate that the UVBE_skin is directly influenced by variations in rotation angles. A significant decrease of approximately 52.70% and 52.10% in UVBE_skin was found when the cheek and nose measurement sites was rotated from 0° to 90°, while a decrease of approximately 62.70% was shown when the forehead measurement sites was rotated from an angle of 0° to 108°. When HBE_skin was compared to the exposure limits (ELs; 30 J·m^-2), the maximum relative risk ratios (RR) for cheek, nose, and forehead were found to be approximately 2.01, 2.40, and 2.90, respectively, which were all measured at a rotation angle of 0°. The maximal increase in the percentage of the average HBE_skin for rotation angles of 60°, 120°, 180°, and 360° facing the sun to ELs were found to be approximately 62.10%, 52.72%, 43.43%, and 26.27% for the cheek; approximately 130.61%, 109.68%, 86.43%, and 50.06% for the nose; and approximately 178.61%, 159.19%, 134.38%, and 83.41% for the forehead, respectively.

Validation of a Sun Exposure Questionnaire Among Subjects with Type 2 Diabetes Residing in South Florida

To validate a sun exposure questionnaire against objective measures of change in skin color and to assess its validity in predicting 25(OH)D in a sample of African Americans and Hispanics with type 2 diabetes. Ninety subjects were enrolled. The sun exposure score was calculated by multiplying the time spent outdoors times the skin exposed score. Skin color was determined by reflectance colorimetry. The relationship between serum 25(OH)D, skin exposure score and stomach skin color was evaluated by a multi-linear regression model. The unadjusted model showed that skin exposure score (P = 0.037), and stomach skin color (P = 0.021) were associated with serum 25(OH)D. This relationship remained significant only for stomach skin color (P = 0.020) after controlling for covariates. It may be possible that the color of the skin is a better predictor of 25(OH)D in this particular population than sun exposure behaviors.

Vitamin D response of older people in residential aged care to sunlight-derived ultraviolet radiation

The aim of this study was to determine the vitamin D response to sunlight ultraviolet radiation in older people. Increases in vitamin D depended on the season of exposure, but the changes were small. Natural sun exposure is not a practical intervention for vitamin D deficiency in this population.

PURPOSE

The purpose of this study is to measure the ultraviolet radiation (UVR) exposure of those in residential aged care in an earlier trial of sunlight exposure and to determine its effect on their vitamin D response.

METHODS

Attendance data, demographic, clinical and biochemical variables for 248 participants were used for a secondary analysis of a previous cluster randomized trial of sunlight exposure and falls. The ambient solar UV Index data were used to calculate the participants' UVR dose. Multiple linear regression was used to test if UVR exposure over 6 months, as measured by the standard erythemal dose (SED), was a predictor of vitamin D response, controlling for age, gender, BMI, calcium intake, baseline vitamin D and season of exposure.

RESULTS

The median 25-hydroxyvitamin D (25OHD) was 32.4 nmol/L at baseline and 34.6 nmol/L at 6 months (p = 0.35). The significant predictors of 25OHD at 6 months were UVR exposures in spring-summer (coefficient = 0.105, 95 % confidence interval (CI) 0.001-0.209, p = 0.05) and autumn-winter (coefficient = 0.056, 95 % CI 0.005-0.107, p = 0.03) and baseline vitamin D (adjusted coefficient = 0.594, 95 % CI 0.465-0.724, p = 0.00). In those starting sunlight sessions in spring, an increase of 1 unit in log SED was associated with 11 % increase in 25OHD.

CONCLUSIONS

Natural UVR exposure can increase 25OHD levels in older people in residential care, but depends on the season of exposure. However, due to inadequate sun exposure, 25OHD did not reach optimal levels. Nevertheless, where sun exposure is encouraged in this group, the focus for the start of exposure should be in the months of spring or autumn, as this timing was associated with a vitamin D response.

Actinic keratosis among seafarers

The aim of this study was to assess the prevalence of UV-induced actinic keratosis and further skin lesions. A newly developed questionnaire about lifetime UV radiation exposure was completed by 514 seafarers. An experienced dermatologist inspected the whole-body skin status of all participants. The questionnaire revealed a pre-employment UV radiation exposure in 104 seafarers, sunbed use in 26 subjects and a median work-related UV radiation exposure at sea of 20 years. The diagnosis of actinic keratoses was made in 94 seafarers and the clinical diagnosis of skin cancers in 48 seafarers (28 basal cell carcinoma, 11 squamous cell carcinoma, 9 malignant melanoma). After age standardisation according to a European reference population, the male European seafarers in this study had a 1.80-fold increased risk of actinic keratosis. Actinic keratoses [OR 1.03 (1.01-1.05)] and squamous cell carcinoma [OR 1.07 (1.01-1.13)] were related to the duration of seafaring time in years. A significant association was also found between actinic keratosis/squamous cell carcinoma and sunlight exposure during home leave [OR 1.67 (1.03-2.81) and OR 6.19 (1.18-32.40)]. Furthermore, the engine room personnel-especially the technical officers-were at higher risk of developing actinic keratosis. Due to the high prevalence of actinic keratosis especially among older seafarers with fair skin, with longer duration of seafaring employment at sea and with higher UV exposure during home leave, more intensive advice should be given on sun protection both at sea and ashore.

Urinary levels of thymine dimer as a biomarker of exposure to ultraviolet radiation in humans during outdoor activities in the summer

The incidence of skin cancer is rising rapidly in many countries, presumably due to increased leisure time exposure to solar ultraviolet radiation (UVR). UVR causes DNA lesions, such as the thymine dimer (T=T), which have been causatively linked to the development of skin cancer. T=T is clearly detectable in urine and may, thereby, be a potentially valuable biomarker of UVR exposure. The objective of this study was to evaluate the relationship between UVR exposure and urinary levels of T=T in a field study involving outdoor workers. Daily ambient and personal exposure of 52 beach lifeguards and agricultural workers to UVR were determined (employing 656 personal polysulphone dosimeters). In 22 of these subjects, daily urinary T=T levels (120 samples) were measured, the area of skin exposed calculated and associations assessed utilizing mixed statistical models. The average daily UVR dose was approximately 600 J/m(2) (7.7 standard erythemal doses), i.e. about 20% of ambient UVR. T=T levels were correlated to UVR dose, increasing by about 6 fmol/µmol creatinine for each 100 J/m(2) increase in dose (average of the three preceding days). This is the first demonstration of a relationship between occupational UVR exposure and urinary levels of a biomarker of DNA damage. On a population level, urinary levels of T=T can be used as a biomarker for UVR exposure in the field.

Quantification of ultraviolet radiation-induced DNA damage in the urine of Swedish adults and children following exposure to sunlight

CONTEXT

DNA damage following exposure to ultraviolet radiation (UVR) is important in skin cancer development. The predominant photoproduct, cyclobutane thymine dimer (T=T), is repaired and excreted in the urine, where it provides a biomarker of exposure.

OBJECTIVE

To quantify urinary T=T levels after recreational sunlight exposure in adults and children.

METHODS

Average UVR doses were measured with personal dosimeters. Urinary T=T was analysed with (32)P-postlabelling.

RESULTS

Background levels of T=T increased significantly following exposure to sunlight. Amounts of T=T in urine of children and adults were not significantly different after adjusting for area of skin exposed and physiological differences. UVR dose and amounts of T=T correlated for both adults and children.

CONCLUSION

Recreational exposure to sunlight in Sweden induces levels of DNA damage, clearly detectable in urine.

Fifty years of changes in UV Index and implications for skin cancer in Australia

Surface ultraviolet (UV) radiation plays an important role in human health. Increased exposure to UV radiation increases the risk of skin cancer. In Australia, public campaigns to prevent skin cancer include the promotion of daily UV forecasts. If all other atmospheric factors are equal, stratospheric ozone decreases result in UV increases. Given that Australia still has the highest skin cancer rates in the world, it is important to monitor Australia's stratospheric ozone and UV radiation levels over time because of the effects cumulative exposure can have on humans. In this paper, two long-term ozone datasets derived from surface and satellite measurements, a radiation code and atmospheric meteorological fields are used to calculate clear-sky UV radiation over a 50-year period (1959-2009) for Australia. The deviations from 1970-1980 levels show that clear-sky UV is on the rise. After the 1990s, an overall annual increase from 2 to 6% above the 1970-1980 levels was observed at all latitudes. Examining the summer and winter deviations from 1970-1980 showed that the winter signal dominated the annual changes, with winter increases almost twice those in summer. With ozone levels not expected to recover to pre-depletion levels until the middle of this century, UV levels are expected to continue to rise. Combined with Australians favoring an outdoor life-style, when temperatures are warmer, under high levels of UV, the associated risk of skin cancer will increase.

Basal and squamous cell carcinoma risks for golfers: an assessment of the influence of tee time for latitudes in the Northern and Southern hemispheres

This study investigates the influence of tee time to determine the relative basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) risk for weekly single round competition golfers located in the Northern and Southern latitude ranges between 25°, 35°, 45° and 55°. A comparative risk methodology, employing annual erythemally effective ultraviolet (UVE) exposure calculations was used to determine BCC and SCC risk factors for golfers using a regular weekly tee time. Relative risk was found to be proportional to golf tee time with mid morning tee times generally presenting the greatest risk in each latitude range. The greatest contribution toward the risk of developing basal and squamous cell carcinoma was found to occur for golfers beginning weekly rounds mid to late morning, with specific risk factors of 1.47 (BCC) and 1.98 (SCC) in the Northern hemisphere compared with similar maximum risk factors of 1.51 (BCC) and 2.08 (SCC) in the Southern hemisphere occurring at comparable morning tee times. Differences in annual UVE exposure between the golfer and non-golfer were the largest determinant of BCC and SCC risk. Generally, these risks were found to decrease with lower latitude although contribution toward overall risk was influenced strongly by the global time zone of each studied golf course site.

Hábitos relacionados à exposição solar dos professores de educação física que trabalham com atividades aquáticas

FUNDAMENTOS: A radiação ultravioleta tem sido considerada um dos mais importantes fatores de risco para o câncer de pele melanoma ou não melanoma. Dessa forma, tem sido aceito que os profissionais que trabalham em atividades ao ar livre apresentam maior risco de desenvolver câncer de pele. OBJETIVO: Identificar os hábitos relacionados à exposição solar dos professores de Educação Física (EF) que trabalham com atividades aquáticas. MÉTODOS: Realizou-se um estudo observacional do tipo transversal com 123 professores de EF, de ambos os sexos, que trabalham com atividades aquáticas, no mínimo, há um ano, com idades entre 20 e 58 anos, utilizando-se um questionário com perguntas abertas e fechadas. RESULTADOS: Do total de informantes, observou-se que 64,2% trabalham diretamente expostos ao Sol e 13,0%, em piscinas com cobertura parcial, dos quais 69,5% o fazem entre 10h e 16h. Do grupo exposto ao Sol, verificou-se que apenas 17,9% sempre se protegem: 14,3% dos homens e 23,1% das mulheres. Contudo, não houve diferenças estatísticas significativas. CONCLUSÕES: A partir dos dados coletados, é possível concluir que o grupo amostral estudado parece encontrarse em situação de risco diante da possibilidade de desenvolver câncer de pele

Diurnal variations in solar ultraviolet radiation at typical anatomical sites

OBJECTIVE

Solar ultraviolet (UV) radiation is an important environmental factor that affects human health. The understanding of diurnal variations of UV radiation at anatomical sites may be helpful in developing ways to protect humans from the harmful effects of UV radiation.

METHODS

In order to characterize the diurnal variations, the UV exposure values were measured at 30 min intervals by using Solar-UV Sensors and a rotating manikin in Shenyang city of China (41 degrees 51'N, 123 degrees 27'E). Measurement data for four representative days (in each of the four seasons respectively) were analyzed.

RESULTS

The diurnal variations in solar UV radiation at the shoulder, the forehead and the chest were similar to those associated with a horizontal control measurement. However, the diurnal variations at the eye and the cheek exhibited bimodal distributions with two peaks in spring, summer and autumn, and a unimodal distribution in winter. The UV exposure peaks at the eye and the cheek were measured at solar elevation angles (SEA) of about 30 degrees and 40 degrees , respectively.

CONCLUSION

The protection of some anatomical sites such as the eye from high UV exposure should not be focused solely on the periods before and after noon, especially in the places and seasons with high SEA.

Patterns of real-time occupational ultraviolet radiation exposure among a sample of outdoor workers in New Zealand

OBJECTIVES

Exposure to solar ultraviolet radiation (UVR) is an occupational health and safety issue for outdoor workers since excessive exposure is associated with negative health outcomes, including eye conditions and skin cancers. The objective of this research was to describe the pattern of UVR exposure experienced by outdoor workers from selected occupations in New Zealand in order to identify the impact of behaviour and work conditions on exposure.

STUDY DESIGN

This paper reports on the occupational UVR exposure arm of a dual arm cross-sectional study that also examined workers' sun protection practices.

METHODS

For five consecutive working days in January-March 2007, electronic dosimeters were used to record the time-stamped UVR exposure of a sample of 77 outdoor workers from three occupations (building, horticulture and roading) in Central Otago, New Zealand.

RESULTS

The geometric mean total daily UVR exposure (between 1100 and 1600 h) was 5.32 standard erythemal doses (SED; 95% reference range 0.28-19.97 SED). The geometric mean total daily UVR exposure as a percentage of the total daily ambient UVR was 20.5% (95% confidence interval 1.4-83.0%). Personal UVR exposure dipped between 1200 h and 1300 h--the same time that ambient UVR peaked--indicating the effect of shade seeking over the lunch period. Personal UVR exposure peaked between 1400 h and 1500 h, alongside decreasing ambient UVR levels, suggesting the influence of behavioural rather than climatic factors. The difference in workers' exposure between 1200 h and 1300 h, and 1400 h and 1500 h was statistically significant for both measured personal exposure (P < 0.005) and exposure calculated as a percentage of concurrent available ambient UVR (P < 0.005).

CONCLUSIONS

All the workers in this study recorded mean daily UVR exposure in excess of the current recommended occupational exposure limits. Only a minority of workers sought shade during their lunch break; most remained in highly exposed conditions. There is no evidence that work tasks which involve substantial sun exposure are being scheduled outside the high UVR period.

Sunlight exposure assessment: can we accurately assess vitamin D exposure from sunlight questionnaires?

The purpose of this review is to summarize the peer-reviewed literature in relation to sunlight exposure assessment and the validity of using sunlight exposure questionnaires to quantify vitamin D status. There is greater variability in personal ultraviolet (UV) light exposure as the result of personal behavior than as the result of ambient UV light exposure. Although statistically significant, the correlation coefficients for the relation between personal report of sun exposure and ambient UV light measured by dosimetry (assessment of radiation dose) are relatively low. Moreover, the few studies to assess the relation between sunlight measures and serum 25-hydroxyvitamin D show low correlations. These low correlations may not be surprising given that personal factors like melanin content in skin and age also influence cutaneous synthesis of vitamin D. In summary, sunlight exposure questionnaires currently provide imprecise estimates of vitamin D status. Research should be directed to develop more objective, nonintrusive, and economical measures of sunlight exposure to quantify personal vitamin D status.

Patterns in the received facial UV exposure of school children measured at a subtropical latitude

Polysulfone (PS) dosimeters have been employed to measure the erythemally effective UV exposure to the vertex, nose, cheek, chin and side facial sites of 45 volunteer high school students from Hervey Bay, Australia (25.3 degrees S 152.9 degrees E). The results of a series of 1 h outdoor sport trials (basketball and soccer) found the mean student facial exposure, determined as the arithmetic average of facial site exposures of unprotected students (no hat) to protected students (hat), varied from 140 +/- 82 J m(-2) (1sigma) to 99 +/- 33 J m(-2) (1sigma), respectively. All hourly student facial exposures recorded over the study period were found to exceed the National Health and Medical Research Council's adopted safe daily limit of 30 J m(-2). Facial exposure relative to the received ambient UV increased to the nose at higher (winter) solar zenith angles (SZAs) compared with lower (summer) SZA ranges for both protected and unprotected students. The protection offered by the broad-brimmed hats was reduced significantly to the lower chin facial site at the higher SZA range, indicating that the style of hat used offers best protection in summer to the upper facial regions at most risk of receiving a high exposure when no hat protection is used. Variations to specific student facial exposure sites were measured between both basketball and soccer players. Variation in student facial exposure was further examined with respect to cloud cover and comparisons to manikin headform measurements were also made. The study results indicate that hats alone are not adequate forms of sun protection in a school environment. Schools aiming to achieve acceptable safe limits of facial exposure may need to further consider the effectiveness of hat protection with increasing SZA, cloud cover and head position relative to the sun that is specific to the scheduled outdoor activity.

Occupational exposure to ultraviolet radiation: the duality dilemma

Human exposure to ultraviolet (UV) radiation is a component of everyday life and a significant hazard for outdoor workers. In addition, a large range of artificial sources also has the potential to provide extreme occupational UV exposure. Even though the human health risks of overexposure to UV are well documented, to date relatively little is known quantitatively about UV exposure. For example, the evidence indicates that workers who are exposed to particular sources (for example, welding arcs) are exposed to extreme UV exposures, despite the use of current control measures. In contrast, increasing evidence points to significant health impacts resulting from underexposure to UV, particularly with the production (or more correctly lack of production) of vitamin D in the skin. The latter poses a serious issue for the work-force, with specific risks for workers lacking adequate sun exposure-underground miners, long-haul flight crews, shift workers, and perhaps indoor workers. Using a risk-management approach, this paper provides a comprehensive review of occupational UV sources, health impact of occupational UV exposure, occupational exposure standards, and levels of exposure in various settings, and discusses the appropriate control measures. In addition, the duality aspect of health impacts from overexposure and underexposure to UV and the associated occupational health implications are specifically explored.

Postal workers' occupational and leisure-time sun safety behaviors (United States)

OBJECTIVES

United States Postal Service letter carriers are exposed to long bouts of UVR and thus are vulnerable to skin cancer. While previous studies have shown that occupational sun protection is often deficient, few studies have examined outdoor workers' behavior during leisure time.

METHODS

Subjects (n = 2,660) self-reported widebrim hat and sunscreen use over the past five workdays and past two non-working days using Likert-type scales. Generalized linear mixed models and generalized estimating equations were used to compare hat and sunscreen rates and predictors during occupational and leisure time.

RESULTS

On average, carriers spent 3.9 h outside during workdays and 3.3 h during non-working days. Sunscreen and widebrim hat use during the workday is low and rates of use are significantly lower during non-working days.

CONCLUSIONS

Sun safety interventions for carriers should encourage sun protection at all times when outdoors.

Compliance and data reliability in sun exposure studies with diaries and personal, electronic UV dosimeters

BACKGROUND/PURPOSE

Skin cancer risk estimations are based on sun exposure data. However, the reliability of collected data in personal ultraviolet (UV) dosimeters studies has not previously been validated. We aimed at investigating the data reliability and subject compliance in a study of sun exposure behaviour among 407 subjects (age range, 4-68 years) during 54 943 days based on time-stamped personal UV dosimeter readings and diary records.

METHODS

By comparing diary records and UV dosimeter readings on a daily basis, we investigated subject compliance, total sun exposure record, reasons for non-responding along with rates of diary completing errors. Efforts to improve compliance were described.

RESULTS

The subject compliance rate was median 93.5% (percent days where the diary was completed and the UV dosimeter was worn). The total sun exposure record rate was median 84.1% (percent of participation days with both UV dosimeter and diary records and where the UV dosimeter was worn). Children, adolescents and golfers had lower sun exposure record rates than the rest of the groups (P<0.05). No significant difference was found between males and females (P=0.15). The 17 non-responders were 10 children, three adolescents, one sun worshipper, two golfers and one gardener. Correctable diary completing mistakes were found in 3.1% of the days. Children made more completing mistakes than adults (P=0.001). The average estimated error rate was 3.3% and was higher for children (6.3%) and adolescents (3.6%) than the adult groups (2.4%).

CONCLUSION

High subject compliance rate and data reliability were obtained because the investigators were service minded but persistent, offering dosimeter maintenance service within 24 h and scrutinized data for errors and mistakes.

Ultraviolet radiation exposure pattern in winter compared with summer based on time-stamped personal dosimeter readings

BACKGROUND

Personal annual ultraviolet (UV) radiation data based on daily records are needed to develop protective strategies.

OBJECTIVES

To compare UV radiation exposure patterns in the winter half-year (October-March) and the summer half-year (April-September) for Danish indoor workers.

METHODS

Nineteen indoor workers (age range 17-56 years) wore personal UV dosimeters, measuring time-stamped UV doses continuously during a year. The corresponding sun exposure behaviour was recorded in diaries. Similar data were collected for 28 volunteers during sun holidays in the winter half-year. The relationship between UV dose and sun exposure behaviour was analysed.

RESULTS

The ambient UV dose during the winter in Denmark (at 56 degrees N) was 394 standard erythema doses (SED) or 10.5% of the annual ambient UV dose. In winter compared with summer the subjects had: (i) a lower percentage of ambient UV radiation, 0.82% vs. 3.4%; (ii) a lower solar UV dose in Denmark, 3.1 SED (range 0.2-52) vs. 133 SED (range 69-363); (iii) less time outdoors per day with positive dosimeter measurements, 10 min vs. 2 h; and (iv) no exposure (0 SED) per day on 77% vs. 19% of the days. Sun holidays outside Denmark in winter gave a median 4.3 SED per day (range 0.6-7.6) and 26 SED (range 3-71) per trip.

CONCLUSIONS

In the winter half-year indoor workers received a negligible UV dose from solar exposure in Denmark and needed no UV precautions. No UV precautions are needed from November to February during holidays to latitudes above 45 degrees N, while precautions are needed the whole year around at lower latitudes.

Ultraviolet exposure patterns of Irish and Danish gardeners during work and leisure

BACKGROUND

Skin cancer, caused by solar ultraviolet (UV) radiation, is a growing problem in Europe. Reliable data on occupational exposure of outdoor workers are needed to develop protective strategies.

OBJECTIVES

To compare UV radiation exposure patterns between outdoor workers in two European populations.

METHODS

Fifty-three gardeners, 31 Irish and 22 Danish (age range 24-69 years) wore personal UV dosimeters, measuring time-stamped UV doses continuously during a 4-month summer period. The current and historical sun exposure pattern was recorded by means of a diary and questionnaire. Assessment of pigmentation, naevi, freckles and solar lentigines was performed. The relationship between UV dose and sun exposure pattern was analysed.

RESULTS

Regarding work days, the Irish had a significantly lower percentage of ambient UV exposure than the Danes, 4.5% vs. 8.1%; a lower UV dose per day, 0.97 standard erythema dose (SED) vs. 1.6 SED; a lower UV dose between 12.00 and 15.00 h, 0.43 SED vs. 0.75 SED; and fewer hours with positive dosimeter measurements, 3.2 h vs. 4.8 h (all values are medians, P < 0.01). Regarding days off work, the same patterns emerged for both UV doses and exposure hours. The Irish had significantly fewer days off than the Danes, median 21 days vs. 49 days, and fewer days with risk behaviour (sunbathing/exposing upper body), median 0 days vs. 8 days (P < 0.01).

CONCLUSIONS

The lower UV exposure received by the Irish gardeners may have been due to indoor breaks during peak ambient UV. Other contributing factors may include differences in natural shade between the parks. Our data suggest that consideration of such factors in scheduling of outdoor work can significantly reduce the occupational UV exposure.

Potential of phenothiazine as a thin film dosimeter for UVA exposures

The research reported in this paper on the changes in absorbance and the calibration of a proposed UVA (320-400 nm) dosimeter have established the phenothiazine-mylar combination as a potential UVA dosimeter for population studies of UVA exposures. The change in optical absorbance at 370 nm was employed to quantify the UVA exposures. This change starts to saturate at a change in absorbance of approximately 0.3. This relates to solar UVA exposures at a sub-tropical site on a horizontal plane of approximately three to four hours. The shape of this calibration curve varies with the season. This can be overcome in the same manner as for polysulfone where the dosimeter is calibrated for the conditions that it will be employed to measure the UVA exposures.

Personal Solar UV Exposure Measurements Employing Modified Polysulphone with an Extended Dynamic Range†¶

Polysulphone dosimeters using a simple to use filter have been developed and tested to provide an extended dynamic measurement range of personal solar UV exposures over an extended period (3 to 6 days). At a Southern Hemisphere subtropical site (27.6 degrees S, 151.9 degrees E), the dynamic range of the filtered polysulphone allowed measurements of erythemal exposures to approximately 100 minimum erythemal dose (MED) for a change in optical absorbance at 330 nm (deltaA330) of 0.35. In comparison, unfiltered polysulphone dosimeters were exposed to approximately 8 MED for the same deltaA330. The error associated with the use of the filtered polysulphone dosimeters is of the order of +/-15%, compared with +/-10% of the unfiltered variety. The developed filtered polysulphone dosimeter system allowed the measurement of erythemal UV exposures over 3 to 6 days at a subtropical site without the need to replace the dosimeters because of saturation. The results show that longer-term measurement programs of personal solar UV have been made more feasible with the use of these polysulphone dosimeters with an extended dynamic range compared with unfiltered polysulphone dosimeters.

Accuracy of annual erythema exposure estimation using different numbers of ambient exposure fractions in the human exposure model

BACKGROUND

The aim was to determine the optimum number of ambient exposure fractions required in the human exposure model for accurate computation of annual erythema effective solar exposure.

METHODS

Ambient exposure fractions were determined on a daily basis over a period of a year in the Rockhampton region using ambient exposure measurements and erythema effective solar exposure measurements at selected body sites of Australia post mail delivery personnel (APMDP). Several values of annual erythema effective exposure for the same body sites were computed using different combinations of ambient exposure fractions on a monthly, seasonally and half-yearly basis in the human exposure model and compared with the measured values.

RESULTS

This method enabled a check on the accuracy of annual erythema effective solar exposure estimation using the different combinations of ambient exposure fractions in the human exposure model. In the worst case there was approximately 35% difference between the measured value and the computed value.

CONCLUSION

The best accuracy was obtained with the use of ambient exposure fractions on a monthly basis where most of the estimated values for the different body sites were within 20% of the measured values.

Description of the use of a risk estimation model to assess the increased risk of non-melanoma skin cancer among outdoor workers in Central Queensland, Australia

BACKGROUND

The aim was to use the measured data on annual exposure to ultraviolet (UV) radiation in the risk estimation model to estimate the increase in risk of Non-Melanomic Skin Cancer (NMSC) among outdoor workers compared to indoor workers in Rockhampton (lat. 23 degrees S), Central Queensland, Australia.

METHODS

Results on annual occupational exposure measured on two occupational groups namely Australia Post Mail Delivery Personnel (APMDP) and Physical Education Teachers (PE) using film badge dosimeters was used in the risk estimation model to determine the increase in risk of NMSC with years of outdoor occupational exposure compared to indoor workers. The sensitivity of the model was tested for variations in recreational and childhood exposure of both groups, as well as occupational exposure of indoor workers.

RESULTS

For APMDP the increase in risk for Basal cell carcinoma (BCC) varied from 1.1 to 3.6 for 5-20 years of exposure and for Squamous cell carcinoma (SCC) the risk varied from 1.2 to 5.5 for the same periods of exposure. For the PE teachers the risk for BCC varied from 1.1 to 1.8 and for SCC the range was 1.1-2.3 for similar exposure periods.

CONCLUSION

The increased risk estimates did not show any significant changes for variations in occupational and recreational exposure. A maximum change of 20% was computed for 25% variation in childhood exposure, which was mainly for the APMDP with high occupational exposure levels and more than 10 years of occupational exposure. The increased risk estimates are useful to identify high risk groups at an early age and implement long-term protective measures against NMSC.

Continuous long-term monitoring of UV radiation in professional mountain guides reveals extremely high exposure

Ultraviolet radiation (UVR) is estimated to be one of the most important risk factors for nonmelanoma and melanoma skin cancers. High occupational UV exposure is assumed to be associated with skin cancer. Mountain guides receive considerable UV doses due to altitude-related increase of UVR and reflection from snow- and ice-covered surfaces. The aim of our study was to assess the annual occupational UV exposure of mountain guides. Spore film test chambers containing spores of Bacillus subtilis (VioSpor) were used as UV dosimeters with a spectral sensitivity profile similar to erythema-weighted data calculated from spectroradiometric measurements. Nine mountain guide instructors carried dosimeters on the sides of their heads on a total of 1,406 working days during one year (July 1999-June 2000). Dosimeters were changed monthly. Measurements of 92 months could be evaluated (4-12 months/mountain guide). The mean individual monthly UV exposure was 107 standard erythema doses (SED) (median 71 SED; range 10-505 SED). The mean annual cumulative UV exposure was 1,097 SED (median 1,273 SED; range 312-1,770 SED) per mountain guide. The mean UV dose per day (4-10 hr) was 6.6 SED (median 5.7 SED; range 0.6-24.2 SED). This is the second study of continuous annual UV dosimetry in a cohort of outdoor workers. Our study showed that it is not sufficient to interpolate annual UV exposure from a few days' measurements. Only long-term dosimetry can give reliable yearly information of UVR load. Median daily UV exposure exceeded limits for UV radiation (e.g., ACGIH effective dose 30 J/m(2) per 8 hr period corresponding to 1.08 SED/day) 6-fold; maximal exposure exceeded these limits 23-fold. These extremely high exposure values are suggestive for an increased risk of skin cancer and thorough epidemiologic studies in the collectives of professional and recreational mountaineering are required.